clk: renesas: Mark rza2_cpg_clk_register static

This is only used in this file, so mark it static to silence a sparse
warning.

Cc: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

drivers/clk/renesas/r7s9210-cpg-mssr.c

@@ -155,7 +155,7 @@ static void __init r7s9210_update_clk_table(struct clk *extal_clk,
 	}
 }
 
-struct clk * __init rza2_cpg_clk_register(struct device *dev,
+static struct clk * __init rza2_cpg_clk_register(struct device *dev,
 	const struct cpg_core_clk *core, const struct cpg_mssr_info *info,
 	struct clk **clks, void __iomem *base,
 	struct raw_notifier_head *notifiers)